In addition, to evaluate whether monitoring serum KL-6 levels in NSCLC patients during the treatment is useful to detect the development of EGFR-TKIs induced ILD or predict the clinical outcome of EGFR-TKIs induced ILD, circulating KL-6 levels were measured in NSCLC patients included in the cohort before and during EGFR-TKIs treatment. The gene discussed is EGFR; the disease is interstitial lung disease.